HANNA HALO Glass Body Gel Filled pH Electrode with Bluetooth® - HI11102

HANNA HALO Glass Body Gel Filled pH Electrode with Bluetooth® - HI11102

The HI11102 HALO is a Bluetooth Smart (Bluetooth 4.0) pH and temperature electrode. This electrode is composed of a glass body and spheric, general purpose glass sensing bulb. The double junction design ensures that the gel electrolyte is free of silver chloride (AgCl) between the sample to be measured and the internal reference cell, resisting clogging and any potential precipitation at the junction. All readings are transmitted directly to the HI2202 edgeblu or a compatible iPad®, iPhone®, or iPod® Touch running the Hanna Lab App.

One press Connect

Easily connect to the Hanna Lab App at the press of a button via Bluetooth wireless technology.

Status Indicator

Visible from a distance, the LED “halo” light flashes to indicate the status of the probe.

Easy to replace battery

The HALO's CR2032 lithium ion battery is easily replaceable and lasts for approximately 500 hours.

Details

The HI11102 HALO is a revolutionary pH electrode that incorporates Bluetooth Smart (Bluetooth 4.0) wireless technology with an application specific design. This electrode has many features that makes it ideal for laboratory use. These features include general purpose (GP) glass, spheric bulb, integrated temperature sensor, glass body, and double reference junction with silver-free gel electrolyte.

General Purpose Glass Formulation

General purpose glass, as the name implies, is a standard glass formulation that is used for general use. A pH electrode with general purpose (GP) glass will have a resistance of 100 megaohms at 25°C and is suited for measuring pH of samples that are at ambient temperatures. The HI11102 is suitable to use with samples that measure from -5 to 80°C (23 to 176°F).

Spheric Glass Tip

The spheric bulb is for general purpose use within laboratory environments and applications that measure aqueous solutions due to its large surface area. Other tip shapes include conic for penetration and flat tip for surface measurements.

Built-in Temperature Sensor

HI11102 features a built-in thermistor temperature sensor that is in the tip of the indicating pH electrode. A thermistor temperature sensor provides for a high accuracy temperature reading and should be as close as possible to the indicating pH electrode in order to compensate for the effect that temperature has on the membrane potential as predicted by the Nernst equation. By having an accurate reading it is possible to provide a temperature compensated reading.

Glass Body

The glass body of the HI11102 is ideal for laboratory use. The glass is resistant to many harsh chemicals and is easy to clean. The glass body also allows for a fast transfer of heat to the internal reference electrolyte. The mV generated by the reference cell is temperature dependent, so the faster thermal equilibrium is reached, the steadier the reference potential.

Single Ceramic Double Junction Reference

The HI11102 is a double junction design. pH electrodes are available as single junction or double junction. See below for a complete description of the differences. The junction also known as a salt bridge is necessary component of the electrical circuit. The movement of ions must flow through the junction for a steady reading. The outer reference has a single ceramic frit. The ceramic is a porous material that is easily fused with the glass body and has a similar expansion coefficient. A single ceramic junction allows the gel electrolyte to flow at a rate of 15-20 μL/hour.

 

Conventional electrodes are normally single junction. As depicted by the figure above, these electrodes have only a single junction between the internal reference wire and the external solution. Under adverse conditions, such as high pressure, high temperature, highly acidic or alkaline solutions, the positive flow of the electrolyte through the junction is often reversed resulting in the ingress of sample solution into the reference compartment. If this is left unchecked, the reference electrode can become contaminated, leading to complete electrode failure. Another potential problem with single junction electrodes is the clogging of the junction due to silver chloride (AgCl) precipitation. Silver can be easily precipitate in samples that contain Tris buffer or heavy metals. When the electrolyte solution makes contact with the sample, some AgCl will precipitate on the external face of the junction. The result is drifty readings obtained from the sensor.

Hanna’s double junction system, as the name implies, has two junctions, only one of which is in contact with the sample as shown in the figure. Under adverse conditions, the same tendency of sample ingress is evident. However, as the reference electrode system is separated physically from the intermediate electrolyte area, the contamination of the electrode is minimized. The likelihood of clogging of the junction is also reduced with a double junction electrode since the outer reference cell uses a fill solution that is “silver-free.” Since there is no silver present, there is no precipitate that can form to clog the junction.